/* Low-level locking access to futex facilities.  Linux version.

   Copyright (C) 2005-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or

   modify it under the terms of the GNU Lesser General Public

   License as published by the Free Software Foundation; either

   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU

   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public

   License along with the GNU C Library.  If not, see

   <http://www.gnu.org/licenses/>.  */

#ifndef _LOWLEVELLOCK_FUTEX_H

#define _LOWLEVELLOCK_FUTEX_H	1

#ifndef __ASSEMBLER__

#include <sysdep.h>

#include <tls.h>

#include <kernel-features.h>

#endif

#define FUTEX_WAIT		0

#define FUTEX_WAKE		1

#define FUTEX_REQUEUE		3

#define FUTEX_CMP_REQUEUE	4

#define FUTEX_WAKE_OP		5

#define FUTEX_OP_CLEAR_WAKE_IF_GT_ONE	((4 << 24) | 1)

#define FUTEX_LOCK_PI		6

#define FUTEX_UNLOCK_PI		7

#define FUTEX_TRYLOCK_PI	8

#define FUTEX_WAIT_BITSET	9

#define FUTEX_WAKE_BITSET	10

#define FUTEX_WAIT_REQUEUE_PI   11

#define FUTEX_CMP_REQUEUE_PI    12

#define FUTEX_PRIVATE_FLAG	128

#define FUTEX_CLOCK_REALTIME	256

#define FUTEX_BITSET_MATCH_ANY	0xffffffff

/* Values for 'private' parameter of locking macros.  Yes, the

   definition seems to be backwards.  But it is not.  The bit will be

   reversed before passing to the system call.  */

#define LLL_PRIVATE	0

#define LLL_SHARED	FUTEX_PRIVATE_FLAG

#ifndef __ASSEMBLER__

#if IS_IN (libc) || IS_IN (rtld)

/* In libc.so or ld.so all futexes are private.  */

# define __lll_private_flag(fl, private)			\

  ({								\

    /* Prevent warnings in callers of this macro.  */		\

    int __lll_private_flag_priv __attribute__ ((unused));	\

    __lll_private_flag_priv = (private);			\

    ((fl) | FUTEX_PRIVATE_FLAG);				\

  })

#else

# define __lll_private_flag(fl, private) \

  (((fl) | FUTEX_PRIVATE_FLAG) ^ (private))

#endif

#define lll_futex_syscall(nargs, futexp, op, ...)                       \

  ({                                                                    \

    INTERNAL_SYSCALL_DECL (__err);                                      \

    long int __ret = INTERNAL_SYSCALL (futex, __err, nargs, futexp, op, \

				       __VA_ARGS__);                    \

    (__glibc_unlikely (INTERNAL_SYSCALL_ERROR_P (__ret, __err))         \

     ? -INTERNAL_SYSCALL_ERRNO (__ret, __err) : 0);                     \

  })

#define lll_futex_wait(futexp, val, private) \

  lll_futex_timed_wait (futexp, val, NULL, private)

#define lll_futex_timed_wait(futexp, val, timeout, private)     \

  lll_futex_syscall (4, futexp,                                 \

		     __lll_private_flag (FUTEX_WAIT, private),  \

		     val, timeout)

#define lll_futex_timed_wait_bitset(futexp, val, timeout, clockbit, private) \

  lll_futex_syscall (6, futexp,                                         \

		     __lll_private_flag (FUTEX_WAIT_BITSET | (clockbit), \

					 private),                      \

		     val, timeout, NULL /* Unused.  */,                 \

		     FUTEX_BITSET_MATCH_ANY)

#define lll_futex_wake(futexp, nr, private)                             \

  lll_futex_syscall (4, futexp,                                         \

		     __lll_private_flag (FUTEX_WAKE, private), nr, 0)

/* Returns non-zero if error happened, zero if success.  */

#define lll_futex_requeue(futexp, nr_wake, nr_move, mutex, val, private) \

  lll_futex_syscall (6, futexp,                                         \

		     __lll_private_flag (FUTEX_CMP_REQUEUE, private),   \

		     nr_wake, nr_move, mutex, val)

/* Returns non-zero if error happened, zero if success.  */

#define lll_futex_wake_unlock(futexp, nr_wake, nr_wake2, futexp2, private) \

  lll_futex_syscall (6, futexp,                                         \

		     __lll_private_flag (FUTEX_WAKE_OP, private),       \

		     nr_wake, nr_wake2, futexp2,                        \

		     FUTEX_OP_CLEAR_WAKE_IF_GT_ONE)

/* Priority Inheritance support.  */

#define lll_futex_wait_requeue_pi(futexp, val, mutex, private) \

  lll_futex_timed_wait_requeue_pi (futexp, val, NULL, 0, mutex, private)

#define lll_futex_timed_wait_requeue_pi(futexp, val, timeout, clockbit, \

					mutex, private)                 \

  lll_futex_syscall (5, futexp,                                         \

		     __lll_private_flag (FUTEX_WAIT_REQUEUE_PI          \

					 | (clockbit), private),        \

		     val, timeout, mutex)

#define lll_futex_cmp_requeue_pi(futexp, nr_wake, nr_move, mutex,       \

				 val, private)                          \

  lll_futex_syscall (6, futexp,                                         \

		     __lll_private_flag (FUTEX_CMP_REQUEUE_PI,          \

					 private),                      \

		     nr_wake, nr_move, mutex, val)

#endif  /* !__ASSEMBLER__  */

#endif  /* lowlevellock-futex.h */